Determining causation of work-related upper extremity disorders.

To determine causation in work-related upper extremity disorders, one must appreciate the philosophical constructs used in establishing causation and have clear definitions of the disorder in question. The preponderance of evidence does not support repetition as a major risk factor for physical injury. Terms such as "repetitive stress," "repetitive strain," and "cumulative trauma" should be abandoned, and we should educate our patients as to the multiple risk factors for upper extremity pain.